Liquid metal multi-sample constant load stress corrosion test device and method

Abstract

The invention belongs to a material performance test technology, and particularly relates to a liquid metal multi-sample constant load stress corrosion test device and method, the device comprises a melting tank, an experiment tank, a liquid pipeline, a cooler, a liquid metal valve and a loading system; the melting tank and the experiment tank are sealed by metal; the melting tank and the experiment tank are communicated by installing a gas pipeline, and an inflation branch, an evacuation branch and a deflation gas circuit are further arranged; the loading system comprises a sample positioning and mounting structure, a guide rail fixed on the experiment tank, and a loading lever connected with the sample positioning and mounting structure. After test preparation, the system is vacuumized and cleaned, then heating and liquid injection are carried out, temperature control adjustment is carried out, and finally a sample is taken out. The stress corrosion test of the material in the flowing liquid metal can be realized, the test condition is closer to the service environment, and a more accurate and more reliable test method is provided for optimization and applicability evaluation of the material.

Description

Technical field [0001] The present invention belongs to the material property testing technology, specifically relates to a liquid metal multi-specimen constant load stress corrosion test apparatus and method. Background [0002] Liquid metals are widely used in the nuclear industry, and the mechanical properties of structural materials will deteriorate under the action of liquid metals, and the plastic toughness will decrease, and even problems such as along the crystal / perforation fracture will occur, which will seriously affect the safe operation of nuclear facilities. There are many factors that affect the degree of performance degradation of structural materials in liquid metals, including temperature, stress, composition, microstructure, degree of wetting, etc. [0003] Stress corrosion refers to the material destruction process produced by the material under the combined action of tensile stress and corrosive medium. Structural materials in the process of processing, serv...

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Problems solved by technology

First, the oxide film on the surface of the material is easily destroyed under the action of tensile stress, and the structural material that loses the protection of the oxide film is directly exposed to the liquid metal condition, and the corrosion and dissolution of the structural material by the liquid metal are strengthened; secondly, under the action of tensile stress The movement of atoms in the material, the diffusion and penetration of liquid metal atoms in the material will all change, which will further affect the mechanical performance of the material; in addition, the liquid metal in practical applications realizes its heat transfer and mass transfer through the circuit and other functions, in order to ensure the purity of liquid metal, most of them are equipped with purification devices such as low-temperature cold traps. The corrosion products of liquid metal to materials in high-temperature areas are precipitated in large quantities in low-temperature areas, resulting in enhanced corrosion effects.

Moreover, the corrosion and diffusion of the liquid metal on the surface of the material in the flowing state will intensify, and even form erosion, which will have an impact on the mechanical properties of the material.

[0004] Due to the difficulties in achieving dynamic sealing at high temperatures, long-term loading (thousands of hours), loading / detection accuracy, etc., there are not many domestic researches on the degradation of mechanical properties of materials under the action of liquid metal, and most of the equipment adopts static corrosion or rotating Corrosion device, single function, or unable to achieve dynamic corrosion test, or unable to achieve load protection

Corrosion tensile test equipment used by relevant international research institutes has defects such as inability to maintain loads stably for a long time during the immersion period or the inability to realize dynamic corrosion tests. The results of a single sample have no reference comparison and cannot accurately reflect the mechanical properties of the material

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